NorthWest Biotherapeutics Inc (NWBO)

[hyperopia]

Doc, without full knowledge of the actual protocols, I think Mike Scott would be the one to ask.

Generally, the time to remove undesired cells or other contaminants is during cell selection in the first step. What you’re discussing is the end product, and at that point, I think it’s just final release viability and sterility testing; the undesired cells at that point are dead or unactivated. I don’t think there’s currently a way to separate and remove those, but they don’t need to if at least 80% are viable. I think Novartis proved that point.

For Kymriah, Novartis was only achieving the commercial specifications the FDA set of 80% viable cells in ~75% of their batches. They were unable to remove the unviable cells, so they had to give away those treatments for free that couldn’t meet spec. I think later Novartis did a study which showed those patient who received those free treatments achieved similar results to those patients whose treatment did meet the commercial specs, so Novartis lobbied the FDA (I think unsuccessfully) to lower the specs to the clinical specification of 70% cell viability.